JP7180589B2 - Light control film, light control system, light control component - Google Patents

Description

The present invention relates to a light control film, a light control system, and a light control member.

Conventionally, various ideas have been proposed for a light control film that is attached to, for example, a window to control the transmission of external light (Patent Documents 1 and 2).
One of such light control films uses liquid crystal. A light control film that uses liquid crystal sandwiches the liquid crystal between two transparent film materials with transparent electrodes, and changes the orientation of the liquid crystal molecules by applying a voltage between the transparent electrodes to reduce the amount of external light transmitted. controlling.

JP-A-03-47392 JP-A-08-184273

As described above, the light control film can control the amount of transmitted light of external light, but the light control film is desired to be used in a wider range of applications than simply changing the amount of transmitted light.

In order to solve the above problems, the present invention provides the following.
(1) a liquid crystal layer including a first electrode, a second electrode, a liquid crystal material, and a dichroic dye, the light transmittance of which varies depending on the potential difference between the first electrode and the second electrode; wherein the liquid crystal layer has a first haze value when the potential difference is the first potential difference, has a second haze value when the potential difference is the second potential difference, and the potential difference is the A light management film having a third haze value that is higher than at least the second haze value for a third potential difference between the first potential difference and the second potential difference.
(2) In (1), the liquid crystal layer has a first transmittance when the potential difference is the first potential difference, and has a second transmittance when the potential difference is the second potential difference. and a third transmittance between the first transmittance and the second transmittance when the potential difference is the third potential difference.
(3) a liquid crystal layer including a first electrode, a second electrode, a liquid crystal material, and a dichroic dye, wherein the light transmittance varies depending on the potential difference between the first electrode and the second electrode; wherein the liquid crystal layer is in a light shielding state when the potential difference is a first potential difference of 0 V, and the transmittance is in the light shielding state when the potential difference is a second potential difference larger than the first potential difference. state, and the haze value becomes maximum when the potential difference is larger than the first potential difference and smaller than the second potential difference. light film.
(4) a liquid crystal layer that includes a first electrode, a second electrode, a liquid crystal material, and a dichroic dye, and whose light transmittance varies depending on the potential difference between the first electrode and the second electrode; wherein the liquid crystal layer is transmissive when the potential difference is a first potential difference of 0 V, and the transmittance is the above when the potential difference is a second potential difference larger than the first potential difference. The haze value is maximized when the light-shielding state is lower than the light-transmitting state, and the potential difference is greater than the first potential difference and the third potential difference is smaller than the second potential difference. dimming film.
(5) In any one of (1), (2), and (3), the liquid crystal layer is in a light shielding state when the potential difference is a first potential difference of 0 V, and the potential difference is the first potential difference. When the second potential difference is greater than the light-transmitting state in which the transmittance is higher than the light-shielding state, the light control film changes from the first potential difference to the second potential difference. Second, the time required for the transmittance to change from the transmittance in the light blocking state to the transmittance in the light transmitting state of 90% is 16 milliseconds or longer.
(6) In any one of (1), (2), and (4), the liquid crystal layer is in a light-transmitting state when the potential difference is the first potential difference of 0 V, and the potential difference is the first potential difference. When the second potential difference is larger than the potential difference, the light-shielding state in which the transmittance is lower than the light-transmitting state occurs, and the light control film changes the potential difference from the second potential difference to the first potential difference. In this case, the time required for the transmittance to change from the transmittance in the light shielding state to the transmittance in the light transmitting state of 90% is 16 milliseconds or longer.
(7) In any one of (1), (2), (3), and (5), the liquid crystal layer is in a light shielding state when the potential difference is the first potential difference of 0 V, and the liquid crystal layer is Where d is the thickness and p is the chiral pitch of the liquid crystal molecules contained in the liquid crystal layer, d/p is 1.1 or more (1.1≤d/p).
(8) In any one of (1), (2), (4), and (6), when the potential difference is the first potential difference of 0 V, the light-transmitting state occurs, and the liquid crystal layer has a thickness of d , where d/p is 0.9 or more and 1.5 or less (0.9≤d/p≤1.5), where p is the chiral pitch of the liquid crystal molecules contained in the liquid crystal layer.
(9) In any one of (1) to (8), the liquid crystal material has dielectric anisotropy, the dielectric constant of the liquid crystal material in the longitudinal direction of the liquid crystal molecules is ε _// , and the _{| Δε |}
(10) A light control system comprising the light control film according to any one of (1) to (9), and a controller that changes the potential difference between the first potential difference and the second potential difference.
(11) In (10), the control unit includes a setting unit that switches the potential difference of the light control film to any one of the first potential difference, the second potential difference, and the third potential difference.
(12) In (10), the control unit includes a setting unit that switches the potential difference of the light control film to either the first potential difference or the second potential difference.
(13) A first laminate having a first substrate and a first electrode, a second laminate having a second substrate and a second electrode, and the first laminate and the second laminate a sandwiched liquid crystal layer, wherein the first substrate and the second substrate are made of glass; the liquid crystal layer includes a liquid crystal material and a dichroic dye; The light transmittance varies depending on the potential difference between the two electrodes, and when the potential difference is a first potential difference of 0 V, a light shielding state occurs, and the potential difference is a second potential difference larger than the first potential difference. , the transmissivity is higher than that of the light shielding state, and the potential difference is a third potential difference that is larger than the first potential difference and smaller than the second potential difference. Secondly, the light modulating member that maximizes the haze value.
(14) A first laminate having a first substrate and a first electrode, a second laminate having a second substrate and a second electrode, and the first laminate and the second laminate a sandwiched liquid crystal layer, wherein the first substrate and the second substrate are made of glass; the liquid crystal layer includes a liquid crystal material and a dichroic dye; The light transmittance varies depending on the potential difference between the two electrodes, and when the potential difference is a first potential difference of 0 V, a light-transmitting state occurs, and the potential difference is a second potential difference larger than the first potential difference. In the case of a potential difference, a light-shielding state in which the transmittance is lower than that in the light-transmitting state is established, and the potential difference is a third potential difference that is larger than the first potential difference and smaller than the second potential difference. In this case, the light modulating member that maximizes the haze value.

The light control film, light control system, and light control member of the present invention include a haze mode that makes the light transmission state (light transmission state) cloudy, and can be used in a wider range of applications.

1 is a cross-sectional view showing a light control film 1 according to first to third embodiments; FIG. 4 shows experimental results of transmittance and haze value when voltages applied to electrodes of a plurality of light control films 1 having different d/p values are changed in the light control film 1 of the first embodiment. It is a block diagram of the light control system 20 provided with the light control film 1 of 1st Embodiment and 2nd Embodiment. In the light control film 1 of 2nd Embodiment, it is an experiment result of the transmittance|permeability and a haze value when the voltage applied to the electrode of the light control film 1 with different d/p is changed. It is a figure explaining the measuring method of the chiral pitch p. It is a block diagram of the dimming system 20 of 3rd Embodiment. FIG. 3 is a diagram showing response time t in the light control film 1 having a normally black structure; It is a figure which shows the measuring method of dielectric anisotropy (DELTA)(epsilon) of a liquid crystal material.

(First embodiment)
(Structure of light control film 1)
FIG. 1 is a cross-sectional view showing a light control film 1 according to a first embodiment of the invention. The light control film 1 is used by being attached with an adhesive layer or the like to a site for light control such as a window glass of a building, a showcase, an indoor transparent partition, a sunroof of a vehicle, etc., and the voltage is changed. Controls transmitted light.

The light control film 1 is a guest-host method light control in which a liquid crystal layer 8 is sandwiched between a film-shaped first laminate 5D and a film-like second laminate 5U, and the electric field applied to the liquid crystal layer 8 is changed to control transmitted light. Film 1.
The first laminate 5D is formed by arranging a first electrode 11, a spacer 12 and a first alignment film 13 on a first substrate 6 which is a transparent film material. The second laminate 5U is formed by disposing a second electrode 16 and a second alignment film 17 on a second substrate 15, which is a transparent film material.
By driving the first electrode 11 and the second electrode 16 provided on the second laminate 5U and the first laminate 5D, the strength of the electric field in the liquid crystal layer 8 changes.

(Base material)
Various transparent film materials applicable to this type of film material can be applied to the first base material 6 and the second base material 15 . In this embodiment, polycarbonate films are applied to the first base material 6 and the second base material 15, but various transparent film materials such as COP (cycloolefin polymer) film, TAC film, PET film, and acrylic film are used. be able to.

(transparent electrode)
The first electrode 11 and the second electrode 16 can be made of various electrode materials that are applicable to this type of film material, and in this embodiment are formed of a transparent electrode material of ITO (Indium Tin Oxide).

(Spacer)
The spacers 12 are provided to define the thickness of the liquid crystal layer 8, and various resin materials can be widely applied. It is produced by coating a photoresist on the substrate 6, exposing it, and developing it.
Note that the spacer 12 may be provided on the second stacked body 5U, or may be provided on both the second stacked body 5U and the first stacked body 5D. Also, the spacer 12 may be a so-called bead spacer.

(Alignment film)
The first alignment film 13 and the second alignment film 17 are produced by rubbing a polyimide resin layer. Note that the first alignment film 13 and the second alignment film 17 can employ various configurations capable of exerting an alignment control force with respect to the liquid crystal material of the liquid crystal layer 8, and are made of so-called photo-alignment films. good too.
In this case, as the photo-alignment material, various materials to which the photo-alignment method can be applied can be applied. For example, a dimerization type material whose orientation does not change due to ultraviolet irradiation after being oriented once is applied. can do. This photodimerization type material is described in "M. Schadt, K. Schmitt, V. Kozinkov and V. Chigrinov: Jpn. J. Appl. Phys., 31, 2155 (1992)", "M. Schadt, H. Seiberle and A. Schuster: Nature, 381, 212 (1996).

(Seal material)
In the light control film 1, a sealing material 19 is arranged so as to surround the liquid crystal layer 8, and the sealing material 19 holds the second laminate 5U and the first laminate 5D together to prevent leakage of the liquid crystal material. be.

(liquid crystal layer)
The liquid crystal layer 8 contains a liquid crystal material and a dichroic dye and is driven by a guest-host system.
(liquid crystal material)
Nematic liquid crystal is used as the liquid crystal material. The liquid crystal material contains a chiral agent, and the chiral pitch p of liquid crystal molecules can be adjusted by adjusting the content of the chiral agent. The chiral pitch is the distance in the thickness direction of the liquid crystal layer 8 when the liquid crystal molecules are twisted for one cycle (360°).
(chiral agent)
A chiral agent is a low-molecular-weight compound having an optically active site and induces a helical structure in nematic liquid crystals. Chiral agents include, for example, S-811, R811, CB-15, MLC6247, MLC6248, R1011 and S1011 (all manufactured by Merck).
(Dichroic dye)
A dichroic dye is a dye whose absorbance in the direction of the long axis of the molecule differs from that in the direction of the short axis. When the orientation state of the liquid crystal molecules changes due to a change in the voltage applied to the light control film 1, the orientation state of the dichroic dye also changes according to the change in the orientation state of the liquid crystal molecules. Examples of dichroic dyes include LSY-116, LSR-401, LSR-405, LSB-278, LSB-350 and LSB-335 (all manufactured by Mitsubishi Kasei Co., Ltd.).

Here, a method for measuring the chiral pitch p will be described. As described above, the chiral pitch is the distance (dimension) in the thickness direction of the liquid crystal layer 8 when the liquid crystal molecules are twisted for one period (360°).
FIG. 5 is a diagram explaining a method of measuring the chiral pitch p. FIG. 5A is a cross-sectional view parallel to the thickness direction of the wedge-shaped cell 30 used for measurement, and FIG. It shows a striped pattern due to the difference in brightness that is sometimes observed.
The wedge cell 30 includes two glass plates 31 and 32 and a base 33 disposed between the two glass plates 31 and 32 to form a wedge shape. A cross section of the wedge-shaped cell 30 parallel to the thickness direction has a wedge shape, and in this embodiment, has a triangular shape as shown in FIG. 5(a). Here, the wedge shape means a shape that is wide at one end and gradually narrows toward the other end, and includes a triangular shape and a trapezoidal shape.

A horizontal alignment film (not shown) is formed on the liquid crystal side surface 32a of the glass plate 32 serving as the bottom surface of the wedge-shaped cell 30 . Therefore, when the guest-host type liquid crystal material is enclosed between the two glass plates 31 and 32 of the wedge-shaped cell 30, the liquid crystal molecules are aligned along the alignment direction of the alignment film, depending on the height of the cell. to turn.

When a guest-host type liquid crystal material is put into the wedge-shaped cell 30, as shown in FIG. This stripe becomes darker as the height H of the cell increases. In addition, the fringes appear at an equal pitch when the liquid crystal rotates 180 degrees.
Therefore, if the width of this stripe is a, the dimension of the wedge-shaped cell 30 in the stripe arrangement direction is L, the largest cell height of the wedge-shaped cell 30 is H, and the chiral pitch is p, then from the similitude ratio, the following is obtained: formula holds.
2×a:L=p:H

From the above, the chiral pitch p is represented by the following formula.
p=2×a×H/L
In this embodiment, the width a of the fringes was measured three times, and the average value was taken as the chiral pitch p. Also, FIG. 5 shows an example in which the entire space formed by the glass plates 31 and 32 and the table 33 is filled with the liquid crystal material. Measurement of the chiral pitch p is possible if a sufficient amount of liquid crystal material is enclosed.

This chiral pitch p is preferably 0.5 μm or more.
When a liquid crystal material having a helical structure is used for the liquid crystal layer 8, a phenomenon occurs in which light having a wavelength of a value obtained by multiplying the average refractive index n of the liquid crystal material by the chiral pitch p is selectively reflected. When the chiral pitch p is less than 0.5 μm, this phenomenon causes selective reflection of light of a specific wavelength in the visible light region, so that the light control film 1 may appear to be colored in a specific color or be toned. The light transmittance of the optical film 1 may decrease. Therefore, this chiral pitch p preferably satisfies the above range.

Also, the thickness (cell gap) d of the liquid crystal layer 8 is preferably 2 μm or more and 20 μm or less.
If the thickness d of the liquid crystal layer 8 is less than 2 μm, it is difficult to manufacture the light control film 1 having such a liquid crystal layer 8, and the production yield of the light control film 1 is greatly reduced. Further, if the thickness d of the liquid crystal layer 8 is more than 20 μm, the amount of liquid crystal material used increases, and the material cost of the light control film 1 increases, which is not preferable. Therefore, the thickness d of the liquid crystal layer 8 is preferably within the above range.
If the liquid crystal layer 8 has a small thickness d, the thickness d of the liquid crystal layer 8 will be smaller than the size of the foreign matter, and the liquid crystal layer 8 will swell only where the foreign matter has entered. As a result, the appearance of the light control film 1 is often deteriorated. However, if the thickness d of the liquid crystal layer 8 is sufficiently large, i.e., if the thickness d of the liquid crystal layer 8 is larger than the size of the foreign matter, such deterioration in appearance can be reduced.

_The liquid crystal material used _for the liquid crystal layer 8 has refractive index anisotropy. The refractive index anisotropy Δn of is represented by the following formula.
Δn= _ne - _no
The larger the value of the refractive index anisotropy Δn of the liquid crystal material, the higher the haze value in the haze state of the light control film 1 . In this embodiment, the refractive index anisotropy Δn of the liquid crystal material is preferably 0.05 or more in order to obtain a sufficient haze value in the haze state (haze mode) in the light control film 1 .

The refractive index anisotropy Δn of this liquid crystal material can be calculated, for example, by the following method.
First, prepare a liquid crystal material that does not contain a dichroic dye, prepare a light control film 1 for measurement that includes this in the liquid crystal layer 8, and prepare a light control film 1 for measurement in which the liquid crystal molecules are tilted (in the case of a normally black structure, , a state in which no voltage is applied, and a state in which a voltage is applied in the case of a normally white structure). Then, the retardation Re and the thickness d of the liquid crystal layer 8 in this state are measured. Here, as an example, an AC voltage of 60 Hz (sine wave) is applied to the light control film 1 for measurement by an AC power supply (eK-FGJ manufactured by Matsusada Precision Co., Ltd.).
Further, the phase difference Re can be measured by a phase difference measuring device (RETS-1200VA manufactured by Otsuka Electronics Co., Ltd.) or the like.
Retardation Re is represented by the following formula, where Δn is the refractive index anisotropy of the liquid crystal material and d is the thickness (cell gap) of the liquid crystal layer 8 .
Re=Δn×d
Therefore, the refractive index anisotropy Δn of the liquid crystal material can be calculated by the following formula.
Δn=Re/d

The light control film 1 of this embodiment has a normally black structure. The normally black structure is a structure in which the transmittance is minimized when no voltage is applied to the liquid crystal, resulting in a black screen.
That is, in this embodiment, when the liquid crystal is p (positive) type, no voltage is applied to the light control film 1, and the liquid crystal molecules are horizontally aligned, the dichroic dye is also horizontally aligned, and the light control film Visible light transmittance of 1 is reduced. Conversely, when a voltage is applied to the light control film 1 and the liquid crystal molecules are vertically aligned, the dichroic dye is also vertically aligned and the visible light transmittance of the light control film 1 increases.

In such a light control film 1, a plurality of voltages (both FIG. 2 shows experimental results of the transmittance and haze values when the potential difference between the electrodes is changed.
The haze value is the ratio of diffuse transmittance (diffuse light transmittance) to total light transmittance. That is, it is an index relating to the transparency of the light control film 1 and represents turbidity (haze). When the haze value is large, the light control film 1 is in a cloudy state (haze state).

As in this embodiment, in the light control film 1 having a normally black structure, when no voltage is applied to the light control film 1 (liquid crystal layer 8), both the liquid crystal molecules and the dichroic dye are light controllable in the longitudinal direction. It is tilted and swirled in the surface direction (direction orthogonal to the thickness direction) of the film 1, and is in a dark state (light-shielding state) with low transmittance. In addition, when a predetermined voltage is applied to the light control film 1 (liquid crystal layer 8), the major axis directions of both the liquid crystal molecules and the dichroic dye are parallel to the thickness direction of the liquid crystal layer 8, resulting in a decrease in transmittance. It becomes a highly bright state (translucent state).
When a voltage between the voltage in the dark state and the voltage in the bright state is applied to the light control film 1 (liquid crystal layer 8), the long axis direction of the liquid crystal molecules and the dichroic dye is the thickness direction of the liquid crystal layer 8. , and this diffuses the light, so that the light control film 1 is in a cloudy state (haze state).

In FIG. 2, the scale on the left vertical axis represents the transmittance, the scale on the right vertical axis represents the haze value, and the horizontal axis represents the applied voltage. As shown, changing the voltage changes the electric field in the liquid crystal layer 8 to change the orientation of the liquid crystal molecules between horizontal and vertical orientations. The orientation direction of the dichroic dye changes in conjunction with the change in the orientation of the liquid crystal molecules, thereby controlling the transmittance of incident light. At this time, the haze value also changes due to the voltage fluctuation. In addition, the solid line in FIG. 2 indicates the transmittance, and the dashed line indicates the haze value.
In the experimental results shown in FIG. 2, the maximum value of the voltage applied to the electrodes of the light control film 1 is 10 V, but this is not limiting. It may be selected as appropriate according to the size of , the design value of the desired transmittance, the environment in which the light control film 1 is used, and the like.

Here, the measuring equipment and the like used for measuring the haze value, transmittance, etc. will be described.
An AC voltage of 60 Hz (rectangular wave) is applied to the light control film 1 by an AC power supply (eK-FGJ manufactured by Matsusada Precision Co., Ltd.). 2 and FIG. 4, which will be described later, the voltage shown on the horizontal axis is the set value in the AC power supply when the voltage is applied to the light control film 1. As shown in FIG.
The haze value and transmittance of the light control film 1 were measured using a haze meter (HM-150 manufactured by Murakami Color Laboratory Co., Ltd.). The haze value measurement method conforms to JIS K7136, and the transmittance measurement method conforms to JIS K7361.

The thickness (cell gap) d of the liquid crystal layer 8 of the light control film 1 corresponds to the height of the spacers 12 of the liquid crystal layer 8 (the dimension of the spacers 12 in the thickness direction of the liquid crystal layer 8), and can be measured by various measuring instruments. is. When the spacers 12 are spherical bead spacers as in this embodiment, the height (thickness d of the liquid crystal layer 8) can be measured with a microscope such as a SEM (scanning electron microscope). Moreover, when the spacer 12 is columnar, the height can be measured with an optical interference type shape measuring instrument.
The method for measuring the chiral pitch p is as described above.
A sample of the light control film 1 used for measuring the haze value and transmittance by applying a voltage had a square shape of 70 mm long and 70 mm wide when viewed from above.
A sample of the light control film 1 used for the measurement uses a guest-host type liquid crystal material as the liquid crystal material of the liquid crystal layer 8 and has a normally black structure.

(1) When d/p is 1.1 (twist 384 degrees) Transmittance: Transmittance increases as the voltage increases.
Haze value: The haze value once rises at a voltage of about 3 V and has a peak value of about 10% at maximum. After that, when the voltage increases and the transmittance also starts to increase, the haze value decreases.
The twist is the rotation (twist) angle of the liquid crystal molecules between the first alignment film 13 and the second alignment film 17 .

(2) When d/p is 1.5 (twist 528 degrees) Transmittance: The transmittance increases as the voltage increases. However, the amount of increase is smaller than in (1).
Haze value: The haze value once rises at a voltage of about 3.9 V and has a peak value of about 18% at maximum. After that, when the voltage increases and the transmittance also starts to increase, the haze value decreases.

(3) When d/p is 1.7 (twist 624 degrees) Transmittance: The transmittance increases as the voltage increases. However, the amount of increase is smaller than in (2).
Haze value: The haze value once increases at a voltage of about 4.0 V, and has a peak value of about 23% at maximum. After that, when the voltage increases and the transmittance also starts to increase, the haze value decreases.

(4) When d/p is 2.0 (twist 720 degrees) Transmittance: Transmittance increases as the voltage increases. However, the amount of increase is smaller than in (3).
Haze value: The haze value once rises at a voltage of about 4.1 V and has a peak value of about 15% at maximum. After that, when the voltage increases and the transmittance also starts to increase, the haze value decreases.

(5) When d/p is 2.7 (960 degree twist) Transmittance: Transmittance increases as the voltage increases. However, the amount of increase is smaller than in (4).
Haze value: At a voltage of about 5.8 V, the haze value rises once and has a peak value of about 22% at maximum. After that, when the voltage increases and the transmittance also starts to increase, the haze value decreases.

Thus, the d/p of the light control film 1 is d/p = 1.1, d/p = 1.5, d/p = 1.7, d/p = 2.0, d/p = 2 7. In any case of 7, the haze value has a peak value in the region where the voltage applied to the electrode has an intermediate value (intermediate voltage between the voltage at which the transmittance is maximized and the voltage at which the transmittance is minimized). That is, it can be seen that there is a range in which the haze value rises.
That is, when d/p is at least 1.1≦d/p, the light control film 1 has a range in which the haze rises at an intermediate voltage value.

FIG. 3 is a block diagram of a light control system 20 including the light control film 1 of this embodiment. The light control system 20 includes a light control film 1 and a control section 21 . This light control film 1 satisfies 1.1≦d/p in d/p. Therefore, in the light control film 1, the voltage applied to the electrodes is an intermediate value between the voltage at which the transmittance is maximized (for example, 10 V in this embodiment) and the voltage at which the transmittance is minimized (0 V). It has a range in which the haze value rises.
The control section 21 has a body section 22 and an adjustment knob 23 rotatable with respect to the body section 22 . When the adjustment knob 23 is rotated with respect to the main body 22, the voltage applied to the electrodes of the light control film 1 changes.
When the adjustment knob 23 is rotated to one end side of the rotatable area (the left side in the drawing, which is labeled “dark”), the voltage applied to the electrode becomes the minimum (0 V), and the transmittance of the light control film 1 also decreases. minimum (dark state).
When the adjustment knob 23 is rotated to the other end side of the rotatable region (the right side in the drawing, which is labeled “Bright”), the voltage becomes maximum (for example, 10 V in this embodiment), and the transmittance becomes maximum ( light state).
In the present embodiment, in the light control system 20, the maximum voltage applied to the electrodes of the light control film 1 is 10 V. However, the maximum voltage applied to the electrodes is not limited to this. It may be appropriately selected according to the size of the film 1, the design value of the desired transmittance, the usage environment of the light control film 1, and the like.

The light control film 1 of this embodiment has a haze region in a region where the voltage applied to the electrode is intermediate between the minimum and maximum voltages. By rotating the adjustment knob 23 to change the voltage applied to the electrodes and selecting the haze state (the central position labeled “Haze” labeled “Dark” and “Bright” in the figure), the electrodes The applied voltage is in a certain region (haze region) where the haze value is maximized, as shown in FIG. When the voltage falls within this haze region, the light control film 1 is in the haze state shown on the right side of FIG. That is, the transparency decreases, and it becomes difficult to observe the opposite side through the light control film 1 like frosted glass. Therefore, when it is used for the glass of a house or a car, for example, it is possible not only to adjust the amount of incident light, but also to make it difficult to see the inside from the outside, and it is also possible to make it difficult to see the outside from the inside.
According to the present embodiment, the light control system 20 including the light control film 1 as described above can change the light control film 1 into a low transmittance state, a high transmittance state, and a frosted glass state. Therefore, the user can appropriately select the state of the light control film 1 .

When the light control film 1 has a normally black structure as in the present embodiment, the peak haze value in the haze state is preferably 5% or more, more preferably 8% or more. More preferably, it is 10% or more.
When the haze value satisfies such a range, sufficient reduction in transparency of the light control film 1 in the haze state (cloudy state) can be ensured, and the observer can recognize that the light control film 1 is in the frosted glass state. clearly visible.

(Second embodiment)
Next, a second embodiment of the invention will be described. The second embodiment differs from the first embodiment in that the light control film 1 of this embodiment has a normally white structure. The normally white structure is a structure in which the transmittance is maximized and the liquid crystal becomes transparent when no voltage is applied to the liquid crystal. A dimming system 20 of the second embodiment is similar to that of the first embodiment.
That is, in the present embodiment, when the liquid crystal is n (negative) type, no voltage is applied to the light control film 1, and the liquid crystal molecules are vertically aligned, the dichroic dye is also vertically aligned, and the light control film The transmittance of 1 is increased. Conversely, when a voltage is applied to the light control film 1 and the liquid crystal molecules are horizontally aligned, the dichroic dye is also horizontally aligned and the transmittance of the light control film 1 decreases.

In the light control film 1 of the second embodiment, when the voltage applied to the electrodes of the plurality of light control films 1 having different ratios (d/p) between the chiral pitch p of the liquid crystal molecules and the thickness d of the liquid crystal layer is changed. FIG. 4 shows the experimental results of the transmittance and haze value of .
The method of measuring the haze value and the transmittance of the light control film 1 of this embodiment is the same as that of the first embodiment, whose experimental results are shown in FIG.
The sample of the light control film 1 of the present embodiment used for measuring the haze value and transmittance had a square shape of 70 mm in length and 70 mm in width in plan view. type liquid crystal material, and has a normally white structure.

As in FIG. 2 of the first embodiment, the scale on the left vertical axis represents the transmittance, the scale on the right vertical axis represents the haze value, and the horizontal axis represents the applied voltage. In addition, the solid line in FIG. 4 indicates the transmittance, and the dashed line indicates the haze value.
In the experimental results shown in FIG. 4, the maximum value of the voltage applied to the electrodes of the light control film 1 is 10 V, but this is not limiting. It may be selected as appropriate according to the size of , the design value of the desired transmittance, the environment in which the light control film 1 is used, and the like.
(1) When d/p is 0.7 (twist 240 degrees) Transmittance: Transmittance is approximately constant at about 71 to 74% at a voltage of 0 to about 1.8 V, but the voltage is 1.8 V. 3.0 V, it drops significantly to about 45%, and then continues to decrease slightly as the voltage increases.
Haze value: The haze value is approximately constant at a voltage of 0 to 10 V, about 1%.

(2) When d/p is 0.8 (twist 280 degrees) Transmittance: Transmittance is approximately constant at about 70% when the voltage is from 0 to about 1.8 V, but when the voltage is from 0.8 V to 3 When the voltage reaches about 0 V, it drops significantly to about 40%, and then continues to decrease slightly as the voltage increases.
Haze value: The haze value is a substantially constant 1% at a voltage of 0 to 10V.

(3) When d/p is 0.9 (twist 320 degrees) Transmittance: Transmittance is approximately constant at about 67% when the voltage is from 0 to about 0.9 V, but when the voltage is from 0.9 to 2 At about 0.5 V, it drops significantly to about 35%, and then continues to decrease slightly as the voltage increases.
Haze value: The haze value has a peak value of about 1.5% at about 2.5 V where the transmittance decreases. Otherwise, it is about 1.0%.

(4) When d/p is 1.0 (twist 360 degrees) Transmittance: Transmittance gradually increases from 0 to about 0.8 V and reaches a maximum of about 65%, and then the voltage is 3 V. When it reaches about 30%, it drops significantly, and then continues to decrease slightly as the voltage increases.
Haze value: At a voltage of about 2.0 V, the haze value has a peak value of about 2.0%. After that, when the voltage rises to about 2.5V, it drops to about 1.0%, and at higher voltages it maintains 1.0%.

(5) When d/p is 1.2 (twist 440 degrees) Transmittance: The transmittance gradually decreases from 0 to about 3.0 V, and then continues to decrease slightly as the voltage increases. .
Haze value: The haze value has a peak value of about 10.0% at a voltage of about 2.0 V at which the transmittance decreases. After that, when the voltage rises to about 3 V, the haze value decreases to about 2.5%, and is maintained at 2.5% at higher voltages.

(6) When d/p is 1.5 (twist 520 degrees) Transmittance: Transmittance gradually decreases from 0 to about 3.0 V, and then continues to decrease slightly as the voltage increases. .
Haze value: When the voltage is about 2.0 V, the haze value has a peak value of about 17.0%. After that, when the voltage rises to about 3.0 V, the haze value decreases to about 2.5%, and is maintained at about 2.5% at higher voltages.

(7) When d/p is 1.7 (twist of 600 degrees) Transmittance: Transmittance is substantially constant at voltages from 0 to 10.
Haze value: There is no haze value peak, and the haze value continues to decrease slightly from 2.5% to 1.0% as the voltage rises.

In this embodiment, when the d/p of the light control film 1 is 0.9≦d/p≦1.5, the voltage applied to the electrodes is the voltage at which the transmittance is maximized and the voltage at which it is minimized. It can be seen that the haze value has a peak value, that is, a range in which the haze value rises in the region having an intermediate value between them.
The light control film 1 of the present embodiment satisfies 0.9≦d/p≦1.5, and a voltage of about 1.5 to 2.5 V is set as the haze region. Then, when the haze region is selected with the adjustment knob, the voltage applied to the electrodes becomes 1.5 to 2.5 V, and the light control film 1 can be brought into the haze state. That is, as in the first embodiment, the transparency is lowered, and it becomes difficult to observe the opposite side through the light control film 1 like frosted glass. That is, the light control system 20 including the light control film 1 of the present embodiment has a low transmittance state, a high transmittance state, and a frosted glass state. Therefore, for example, it can be used for the glass of a house or a car, and not only can it adjust the amount of incident light, but it can also make it difficult to see the inside from the outside and the outside from the inside.

When the light control film 1 has a normally white structure as in the present embodiment, the peak haze value in the haze state is preferably 1.5% or more, more preferably 5% or more. is more preferable, and 10% or more is even more preferable.
When the haze value satisfies such a range, sufficient reduction in transparency of the light control film 1 in the haze state (cloudy state) can be ensured, and the observer can recognize that the light control film 1 is in the frosted glass state. clearly visible.

(Third Embodiment)
FIG. 6 is a block diagram of the dimming system 20 of the third embodiment.
In the third embodiment, the dimming system 20 can be switched between only two states: a state with low transmittance (light shielding state, dark state) and a state with high transmittance (transmitting state, bright state). is different from the first and second embodiments.
A light control system 20 of the third embodiment includes a light control film 1 and a controller 21 . The control unit 21 has a main unit 22 and an adjustment knob 23, and can switch the voltage applied to the electrode of the light control film 1 by rotating the adjustment knob 23 with respect to the main unit 22. . Although FIG. 6 shows an example in which the light control system 20 of the third embodiment includes the adjustment knob 23, the present invention is not limited to this, and a switch, button, or the like may be used to switch the voltage applied to the electrodes.
In the light control system 20 of the third embodiment, the light control film 1 having the normally black structure shown in the first embodiment may be used, or the light control film having the normally white structure shown in the second embodiment may be used. 1 may be used. Here, as an example, an example using the light control film 1 having the normally black structure shown in the first embodiment will be described.

First, the light control system 20 of this embodiment will be described.
In the light control system 20 of the present embodiment, when the position of the adjustment knob 23 is on one end side of the rotatable region (“dark” side on the left side in the figure), the voltage applied to the electrodes is the minimum (0 V), and light control is performed. The transmittance of the film 1 is also minimized (dark state).
Further, when the adjustment knob 23 is positioned at the other end of the rotatable region (“bright” side on the left side in the drawing), the voltage applied to the electrodes is maximized, and the transmittance of the light control film 1 is also maximized (bright state). ).
In this embodiment, as an example, the light control film 1 described in the first embodiment is used as the light control film 1 included in the light control system 20, and the maximum voltage applied to the electrodes is 10 V. The maximum value of the voltage applied to the electrodes will be described by giving an example that can be set. It may be selected as appropriate, and may be a value greater than 10V or a value less than 10V.

In this embodiment, the adjustment knob 23 can select only one of "dark" and "bright" for the transmittance of the light control film 1, as described above. That is, in the present embodiment, instead of maintaining the voltage applied to the light control film 1 by the adjustment knob 23 at an intermediate value between the minimum and the maximum as in the first and second embodiments, It can be switched to either minimum or maximum.
In the light control system 20 of the present embodiment, for example, when the voltage applied to the light control film 1 is switched from the minimum value to the maximum value, the light control film 1 changes from the horizontal axis of FIG. is assumed to be the elapsed time, and the light control film 1 changes from the dark state to the haze state and then to the bright state.

In this embodiment, when the voltage applied to the light control film 1 is switched from the minimum value to the maximum value (that is, when the adjustment knob 23 is switched from “dark” to “bright”), the light control film 1 Response is the time it takes for the transmittance to reach a value corresponding to 90% of the maximum value from the minimum value (the time it takes for the transmittance in the light blocking state to reach the transmittance corresponding to 90% of the transmittance in the light transmitting state) The time is preferably 16 milliseconds or more, more preferably 100 milliseconds or more, and even more preferably 200 milliseconds or more.
In this embodiment, by setting the response time of the light control film 1 in the light control system 20 within the above range, when switching the voltage applied to the light control film 1 from the minimum value to the maximum value, the light control film 1 changes from a dark state through a haze state to a bright state, and the haze state is sufficiently visible to an observer. As a result, when the light control film 1 is switched between "dark" and "bright", the appearance of the outside scenery through the light control film 1 does not change momentarily, but the cloudy state (haze state) is changed. Since it is visually recognized by an observer as if it changes over time, it is possible to soften the impression of a change in the appearance of the external scenery through the light control film 1 at the time of switching.

In addition, the time required for the transmittance of the light control film 1 to reach a value corresponding to 90% of the maximum value from the minimum value (from the transmittance in the light blocking state to the transmittance corresponding to 90% of the transmittance in the light transmitting state The response time, which is the time to ) can be measured in the following manner.
First, the light control film 1 is placed on a sample stage of a microscope (polarizing microscope, Olympus BX51-XP). An optical microscope that does not have a polarizing function can also be used as the microscope.
Next, a function generator (EAVE FACTORY WF1974, NF Circuit Design Block Co., Ltd.) repeatedly applies a minimum voltage value and a maximum voltage value to the light control film 1 placed on the sample stage every 10 seconds. The minimum voltage value is 0 V, and the maximum voltage value can be appropriately selected according to the size of the light control film 1 and the like. Here, the light control film 1 has a normally black structure, and as an example, the maximum voltage value is set to 20 V (60 Hz, rectangular wave).

Transmitted light when the voltage applied to the light control film 1 is the minimum voltage value and the maximum voltage value is converted into a voltage signal by an optical sensor (Hamamatsu Photonics Co., Ltd. C8137-02), and an oscilloscope (Tektronix Co., Ltd. TDS 1012B ).
FIG. 7 is a diagram showing the response time t in the light control film 1 having a normally black structure. FIG. 7 shows the screen of the oscilloscope, the vertical axis represents voltage (V) and the horizontal axis represents time (milliseconds: ms).
Since the light control film 1 has a normally black structure, when the voltage applied to the electrode is the minimum voltage value (here, 0 V), the light control film 1 is in a dark state (light shielding state), and the maximum voltage value (here, 20 V), the light control film 1 is in the bright state (light-transmitting state). From the rise of the signal at the time of change from the dark state to the bright state (at the time of change from the minimum voltage value to the maximum voltage value) by switching the voltage value until 90% of the maximum value of the signal (90% of the maximum voltage value) The response time t can be obtained by reading the time of .

The liquid crystal material used _for the liquid crystal layer 8 of the light control film 1 has dielectric anisotropy (dielectric anisotropy). The dielectric anisotropy Δε of the liquid crystal material is given by the following formula, where ε _⊥ is the dielectric constant in the minor axis direction of the molecule.
Δε＝ε _// －ε _⊥
In the present embodiment, the absolute value |Δε|=|ε _// -ε _⊥ | of the dielectric anisotropy of the liquid crystal material is preferably 100 or less, more preferably 60 or less, and 30 or less. It is even more preferable to have The larger the absolute value |Δε| of the dielectric anisotropy, the faster the response speed of the liquid crystal molecules when a voltage is applied to the light control film 1, and the larger the value of the absolute value |Δε| of the dielectric anisotropy. The smaller is, the slower the response speed of the liquid crystal molecules when a voltage is applied to the light control film 1 .

Therefore, in the present embodiment, when the absolute value of dielectric anisotropy |Δε| can be done. Therefore, when switching the light control film 1, the external scenery does not change instantaneously, but changes through a cloudy state (haze state), so that the appearance of the external scenery through the light control film 1 at the time of switching is changed. It can soften the impression of a change in direction.
When a plurality of types of liquid crystal materials are mixed and used in the liquid crystal layer 8, it is preferable that the liquid crystal molecules having the smallest absolute value |Δε| of dielectric anisotropy satisfy the above range. It is more preferable that the dielectric anisotropy absolute value |Δε| satisfies the above range from the viewpoint of further enhancing the effect of softening the impression such as the change in appearance of the external scenery at the time of switching.

The absolute value |Δε| of the dielectric anisotropy of the liquid crystal material can be obtained, for example, by the following method.
FIG. 8 is a diagram showing a method of measuring the dielectric anisotropy Δε of the liquid crystal material.
As shown in FIG. 8, an AC power supply E (eK-FGJ manufactured by Matsusada Precision Co., Ltd.), a light control film 1 and a resistor R are connected in series. The AC power supply E has a frequency f of 60 Hz (sine wave) and a resistance value R ₁ of the resistor R of 10 kΩ.
The power supply of the AC power supply E is switched on/off (application of voltage to the light control film 1 is switched on/off), and the state in which the liquid crystal molecules stand in the thickness direction of the liquid crystal layer 8 (that is, the long axis of the liquid crystal molecules) direction) and the dielectric constant in the state where the liquid crystal molecules are tilted (that is, in the minor axis direction of the liquid crystal molecules), and the difference Δε can be obtained.

The dielectric constant (relative dielectric constant) _εr of the liquid crystal material is defined by: C the dielectric capacity of the liquid crystal layer 8 (light control film 1); S the area of the liquid crystal layer 8; d the thickness of the liquid crystal layer 8; is given by the following _equation .
C= _εr × _ε0 ×S/d
Therefore, ε _r is given by the following equation.
ε _r =C×d/(S×ε ₀ )
ε ₀ =8.85×10 ⁻¹² and the thickness d of the liquid crystal layer 8 and the area S of the liquid crystal layer 8 can be measured and calculated respectively.
Therefore, by measuring the dielectric capacitance C when the AC power supply E is turned on and off, the dielectric constant ε _r That is, the dielectric constant ε _// in the long-axis direction of the liquid crystal and the dielectric constant ε _r in the state where the liquid crystal molecules are tilted, that is, the dielectric constant ε _⊥ in the short-axis direction of the liquid crystal molecules can be calculated.

In the circuit shown in FIG. 8, the voltage _Vc associated with the light control film 1 is expressed by the following equation, where _VR is the voltage applied to the resistor and _VE is the voltage of the AC power supply.
V _c = √(V _E ² -V _R ² )
Here, it is obtained by measuring the voltage V _R applied to the resistor and the voltage V _E of the AC power supply device with a tester (CDM-2000D manufactured by Custom Co., Ltd.), not shown.
Assuming that the current passing through the liquid crystal layer 8 (light control film 1) is I _c and the frequency of the AC power supply is f, the voltage V _c associated with the light control film 1 is also expressed by the following equation.
V _c =I _c ×1/(2π×f×C)
Therefore, the capacitance C of the liquid crystal layer 8 is obtained by the following formula. where f=60 Hz, I _c =V _R /R ₁ and R ₁ =10 kΩ.
C= _Ic *1/(2π*f* _Vc )
From the capacitance C of the liquid crystal layer 8 when the AC power supply E is turned on and off, which is obtained by the above equation, and the above equation ε _r =C×d/(S×ε ₀ ), the liquid crystal molecules The dielectric constant ε _// in the long axis direction of the liquid crystal molecules and the dielectric constant ε _⊥ in the short axis direction of the liquid crystal molecules are obtained. | is obtained.

Also in this embodiment, the refractive index anisotropy Δn of the liquid crystal molecules is preferably 0.05 or more in order to obtain a sufficient haze value in the haze state (haze mode) in the light control film 1. .

Further, when the light control film 1 has a normally black structure as in the present embodiment, the peak value of the haze value in the haze state is preferably 5% or more, more preferably 8% or more. More preferably, it is 10% or more. By satisfying such a range, the haze state between the dark state and the bright state can be easily visually recognized by the observer, the impression at the time of switching between the dark state and the bright state can be softened, and the dark state can be changed to the bright state. A stimulus received by a sudden change in brightness to a state can be reduced.

In the light control system 20 of the present embodiment, when using the light control film 1 having a normally white structure as shown in the second embodiment, the voltage applied to the light control film 1 is changed from the maximum value to the minimum value. When switching (that is, when the adjustment knob 23 is switched from "dark" to "bright"), the time required for the transmittance of the light control film 1 to reach a value corresponding to 90% of the maximum value from the minimum value ( The response time, which is the time from the transmittance in the light blocking state to the transmittance corresponding to 90% of the transmittance in the light transmitting state, is preferably 16 milliseconds or more, more preferably 100 milliseconds or more. Preferably, it is more preferably 200 milliseconds or longer.

Even when the light control film 1 has a normally white structure, the transmittance in the light blocking state is changed to the transmittance corresponding to 90% of the transmittance in the light transmitting state by the same device as in the case of the normally black structure. A response time, which is the time it takes to reach the target, can be obtained.
However, the light control film 1 has a normally white structure, and the maximum voltage value applied to the electrodes of the light control film 1 by the function generator is, for example, 10 V (60 Hz, rectangular wave). The maximum voltage value can be appropriately selected according to the size of the light control film 1 and the like.
Further, since the light control film 1 has a normally white structure, when the voltage applied to the electrode is the minimum voltage value (here, 0 V), the light control film 1 is in the bright state (light-transmitting state), and the maximum voltage is value (here, 10 V), the light control film 1 is in the dark state (light blocking state).
Then, by reading the time from the rise of the signal when the voltage value is switched from the dark state to the bright state until the signal intensity reaches 90% of the maximum value, the transmittance of the light-shielding state of the light control film 1 A response time, which is the time it takes to reach a transmittance corresponding to 90% of the transmittance in the transmissive state, can be obtained.

When the light control film 1 has a normally white structure, the peak haze value in the haze state is preferably 1.5% or more, more preferably 5% or more, and 10%. It is more preferable that it is above. By satisfying such a range, the haze state between the dark state and the bright state can be easily recognized by the observer, and the impression at the time of switching from "dark" to "bright" can be softened. It is possible to reduce the stimulus received by a sudden change in brightness from the state to the bright state.

The peak value of the preferred haze value when the light control film 1 has a normally white structure is smaller than that when it has a normally black structure because when the light control film 1 changes from a bright state to a dark state via a haze state, This is because the transmittance in the haze state is also high, so that the haze state is more easily visible.

(deformed form)
Various modifications and changes are possible without being limited to the embodiments described above, and they are also within the scope of the present invention.
(1) In each embodiment, the substrates 6 and 15 are film-shaped members made of resin. A plate-shaped member may be used, and the light control film 1 may be a non-film-shaped light control member.

In addition, although each embodiment and modification can also be combined and used suitably, detailed description is abbreviate|omitted. Moreover, the present invention is not limited by the embodiments and the like described above.

Reference Signs List 1 light control film 5D first laminate 5U second laminate 6 first substrate 8 liquid crystal layer 11 transparent electrode 12 spacer 13 first alignment film 15 second substrate 16 second electrode 17 second alignment film 19 sealing material 20 Light control system 21 control unit 22 main unit 23 adjustment knob

Claims (13)

a first electrode;
a second electrode;
a liquid crystal layer containing a liquid crystal material and a dichroic dye, the light transmittance of which varies depending on the potential difference between the first electrode and the second electrode;
The liquid crystal layer is
when the potential difference is a first potential difference, having a first haze value;
when the potential difference is a second potential difference, having a second haze value;
a third haze value higher than at least the second haze value when the potential difference is a third potential difference between the first potential difference and the second potential difference;
In the liquid crystal material, the refractive index anisotropy Δn of the liquid crystal material is represented by Δn=n _e −n _o , where n _o is the refractive index for the ordinary ray and _{n e} is the refractive index for the extraordinary ray. ≧0.05 ,
The liquid crystal material has dielectric anisotropy,
Let ε _// be the dielectric constant of the liquid crystal material in the long axis direction and ε _⊥ be the dielectric constant of the short axis direction of the liquid crystal molecules , and the absolute value of the difference between them |Δε|=|ε _// -ε When _⊥ ｜
|Δε| is 30 or less,
dimming film. The liquid crystal layer is
having a first transmittance when the potential difference is the first potential difference;
having a second transmittance when the potential difference is the second potential difference;
having a third transmittance between the first transmittance and the second transmittance when the potential difference is the third potential difference;
The light control film according to claim 1. a first electrode;
a second electrode;
a liquid crystal layer containing a liquid crystal material and a dichroic dye, the light transmittance of which varies depending on the potential difference between the first electrode and the second electrode;
The liquid crystal layer is
When the potential difference is a first potential difference of 0 V, a light shielding state is established,
when the potential difference is a second potential difference larger than the first potential difference, a transmissive state having a higher transmittance than the light shielding state is established;
When the potential difference is a third potential difference that is larger than the first potential difference and smaller than the second potential difference, the haze value becomes maximum,
In the liquid crystal material, the refractive index anisotropy Δn of the liquid crystal material is represented by Δn=n _e −n _o , where n _o is the refractive index for the ordinary ray and _{n e} is the refractive index for the extraordinary ray. ≧0.05 ,
The liquid crystal material has dielectric anisotropy,
Let ε _// be the dielectric constant of the liquid crystal material in the long axis direction and ε _⊥ be the dielectric constant of the short axis direction of the liquid crystal molecules , and the absolute value of the difference between them |Δε|=|ε _// -ε When _⊥ ｜
|Δε| is 30 or less,
dimming film. a first electrode;
a second electrode;
a liquid crystal layer containing a liquid crystal material and a dichroic dye, the light transmittance of which varies depending on the potential difference between the first electrode and the second electrode;
The liquid crystal layer is
When the potential difference is a first potential difference of 0 V, a translucent state is established,
when the potential difference is a second potential difference larger than the first potential difference, a light shielding state in which the transmittance is lower than that in the light transmitting state is established;
When the potential difference is a third potential difference that is larger than the first potential difference and smaller than the second potential difference, the haze value becomes maximum,
In the liquid crystal material, the refractive index anisotropy Δn of the liquid crystal material is represented by Δn=n _e −n _o , where n _o is the refractive index for the ordinary ray and _{n e} is the refractive index for the extraordinary ray. ≧0.05 ,
The liquid crystal material has dielectric anisotropy,
Let ε _// be the dielectric constant of the liquid crystal material in the long axis direction and ε _⊥ be the dielectric constant of the short axis direction of the liquid crystal molecules , and the absolute value of the difference between them |Δε|=|ε _// -ε When _⊥ ｜
|Δε| is 30 or less,
dimming film. The liquid crystal layer is
When the potential difference is a first potential difference of 0 V, a light shielding state is established,
when the potential difference is a second potential difference larger than the first potential difference, a transmissive state having a higher transmittance than the light shielding state is established;
In the light control film, when the potential difference changes from the first potential difference to the second potential difference, the transmittance in the light blocking state changes to the transmittance of 90% in the light transmitting state. is 16 milliseconds or more to
The light control film according to any one of claims 1, 2 and 3. The liquid crystal layer is
When the potential difference is a first potential difference of 0 V, a translucent state is established,
when the potential difference is a second potential difference larger than the first potential difference, a light shielding state in which the transmittance is lower than that in the light transmitting state is established;
In the light control film, when the potential difference changes from the second potential difference to the first potential difference, the transmittance in the light blocking state changes to the transmittance of 90% in the light transmitting state. is 16 milliseconds or more to
The light control film according to any one of claims 1, 2 and 4. The liquid crystal layer is
A light shielding state occurs when the potential difference is the first potential difference of 0V,
When the thickness of the liquid crystal layer is d and the chiral pitch of the liquid crystal molecules contained in the liquid crystal layer is p,
d/p is 1.1 or more (1.1 ≤ d/p),
The light control film according to any one of claims 1, 2, 3 and 5. When the potential difference is the first potential difference of 0 V, a light-transmitting state is established,
When the thickness of the liquid crystal layer is d and the chiral pitch of the liquid crystal molecules contained in the liquid crystal layer is p,
d/p is 0.9 or more and 1.5 or less (0.9 ≤ d/p ≤ 1.5),
The light control film according to claim 1, claim 2, claim 4, or claim 6. A light control film according to any one of claims 1 to 8 ;
a control unit that changes the potential difference between the first potential difference and the second potential difference;
Dimming system with. The control unit includes a setting unit that switches the potential difference of the light control film to any one of the first potential difference, the second potential difference, and the third potential difference.
A dimming system according to claim 9 . The control unit includes a setting unit that switches the potential difference of the light control film to either the first potential difference or the second potential difference.
A dimming system according to claim 9 . a first laminate having a first substrate and a first electrode;
a second laminate having a second substrate and a second electrode;
a liquid crystal layer sandwiched between the first laminate and the second laminate,
The first base material and the second base material are made of glass,
the liquid crystal layer includes a liquid crystal material and a dichroic dye, and the light transmittance varies depending on the potential difference between the first electrode and the second electrode;
When the potential difference is a first potential difference of 0 V, a light shielding state is established,
when the potential difference is a second potential difference larger than the first potential difference, a transmissive state having a higher transmittance than the light shielding state is established;
When the potential difference is a third potential difference that is larger than the first potential difference and smaller than the second potential difference, the haze value becomes maximum,
In the liquid crystal material, the refractive index anisotropy Δn of the liquid crystal material is represented by Δn=n _e −n _o , where n _o is the refractive index for the ordinary ray and _{n e} is the refractive index for the extraordinary ray. ≧0.05 ,
The liquid crystal material has dielectric anisotropy,
Let ε _// be the dielectric constant of the liquid crystal material in the long axis direction and ε _⊥ be the dielectric constant of the short axis direction of the liquid crystal molecules , and the absolute value of the difference between them |Δε|=|ε _// -ε When _⊥ ｜
|Δε| is 30 or less,
dimming component. a first laminate having a first substrate and a first electrode;
a second laminate having a second substrate and a second electrode;
a liquid crystal layer sandwiched between the first laminate and the second laminate,
The first base material and the second base material are made of glass,
the liquid crystal layer includes a liquid crystal material and a dichroic dye, and the light transmittance varies depending on the potential difference between the first electrode and the second electrode;
When the potential difference is a first potential difference of 0 V, a translucent state is established,
when the potential difference is a second potential difference larger than the first potential difference, a light shielding state in which the transmittance is lower than that in the light transmitting state is established;
When the potential difference is a third potential difference that is larger than the first potential difference and smaller than the second potential difference, the haze value becomes maximum,
In the liquid crystal material, the refractive index anisotropy Δn of the liquid crystal material is represented by Δn=n _e −n _o , where n _o is the refractive index for the ordinary ray and _{n e} is the refractive index for the extraordinary ray. ≧0.05 ,
The liquid crystal material has dielectric anisotropy,
Let ε _// be the dielectric constant of the liquid crystal material in the long axis direction and ε _⊥ be the dielectric constant of the short axis direction of the liquid crystal molecules , and the absolute value of the difference between them |Δε|=|ε _// -ε When _⊥ ｜
|Δε| is 30 or less,
dimming component.

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